According to your game choices consoles are not suitable for you, best upgrade your PC. But, if you do, Xbox 360 is clearly a winner. X360 have some unique titles that can categorized under RPG. Fable 2, Lost Odyssey and Too Human, for ex. Fable 2 is a great game and provides the gamer lots of freedom. Although i am not quite fond of japanize RPGs, Lost Odyssey amazed me, i could not play other games until i finished it last year. The story was well writen. Not, some boy saving a kingdom. It resembles Planescape Torment in this aspect, and clearly a must buy if you have X360. Too Human is an action RPG in the setting that combines norse mythology and cybernetics. This game did not sell well, but i liked it anyway. Different control style rather than traditional console control style, but try it.
Then there is Fallout 3, Sacred 2, Mass Effect which also shows itself on PC platform. But, i played Fallout 3 on my console, because its controller is so comfort, and not giving my wrists aches after long gaming sessions, not like keyboard and mouse.
Also there are some JRPG titles: Infinite Undiscovery, Blue Dragon (both two are unique to X360), The Last Remnant, Eternal Sonata, Tales Of Vesperia.
Also lots of RPGs will come for X360 as well: Alpha Protocol, Dragon Age, Mass Effect 2, Divinity 2, Risen, Arcania: A Gothic Tale, Fallout: New Vegas, Bioshock 2.
Add to this the non RPG titles like Gears Of War 2, Alan Wake, Brutal Legend and X360 is definitely a must buy for most gamers.
If you want to buy it buy the elite version which comes with an 120 gb harddisc. Therefore you can install games on your harddisc and play games with less loading times and noise.